Cooling system



R 0 L Y A T Q n COOLING SYSTEM Filed June 8, 1935 3 Sheets-Sheet 2 omiel 0L Taylar 3 W g wtww.

R O L Y A T a D COOLING SYSTEM 3 Shets-Sheet 3 Filed June 8, 1935 Dmzz'eZ 6 Taylor inter! Nov. 19, 1940 UNITED STATES PATENT OFFICE 2,222,159 cooLING SYSTEM Daniel G. Taylor, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a. corporation of Delaware Application June 8, 1935, Serial No. 25,635

20 Claims.

be maintained within the buildingleven though the heat gain to the building may solar radiation or wind.

The present invention also has the advantage oi placement of the thermal control means at a position where it cannot be conveniently tambe varied by pered with by the occupants oi the building to be cooled. Where thermostats are located in any room to be cooled, the tenant may open the window of that room and thereby raise the temperature of the room sufllciently to start the cooling plant and thereby cool the other rooms of the building when such cooling is notneeded. This last contingency occurs where a single cooling plant serves a number of rooms and where the thermostat in one of the rooms is adapted to control the cooling plant.

It is therefore an object of this invention to provide a cooling system for a building that respends directly to outdoor atmospheric conditions to maintain given temperatures within the building regardless of the efiect of solar radiation or wind.

It is another object of this invention to pro-- ride a cooling system for a building wherein the cooling system is under the control of a singlecontrol unit so located that it cannot be tampered with by the occupants of the building or be affected by local temperature conditions in the building whereby an average temperature may be maintained throughout the building.

It is still another object of this invention to provide a cooling system of the class described wherein the building temperature may be maintained at a constant predetermined value regardless of outdoor atmospheric conditions or wherein the temperature of the building may rise upon an increase in outdoor temperature.

A further object of this invention is to provide means for adjusting a control system fora cooling apparatus to compensate for changes in the cooling load as caused by the congregation of a large number of people within the building whereby the building temperature may be maintalned at a desired value whether there be many or few people within the building.

A still further object is to provide a novel control apparatus for accomplishing the above results.

Other objects and advantages will become apparent to those skilled in the art upon reference to the accompanying specification, claims and drawings, in which drawings:

Fig. 1 is a diagrammatic view of one form of my invention.

Fig. 2 is a diagrammatic view of another form of my invention, and

Fig. 3 is a diagrammatic view of still another form of my invention.

For purposes of illustration, I have shown in Fig. 1 my cooling system applied to a building.

having a side wall I0 and a plurality of spaces to be cooled, one of which is shown at II. In each of the spaces II to be cooled are located one or more grills l2 which connect the spaces to be cooled with an air duct l3. Air flows into the air ducts l3 from a main air duct ll .which is supplied with air by means of a supply duct l5. Air is forced through the various ducts and grills into the spaces to be cooled by means of a fan It connected to an air conditioning unit I'I.

Located in the air conditioning unit ll is a cooling coil l8 over which the air delivered to the spaces to be cooled is passed. By properly controlling the cooling eflect of the cooling coil IS, the temperature of the air delivered to the spaces to be cooled, and consequently, the temperature of the spaces may be accurately controlled.

The fan "16 is driven by a conventional electric motor l9 which receives its energy from line wires 20 and 21 leading from some source of power (not shown). A wire 22 connects the line wire 20 with a contact 23. A switch arm 24 cooperates with the contact 23 and is connected by a wire 25 to the electric motor IS. The electric motor I9 is in turn connected by a wire 26 to the other line wire 2|. Upon movement of switch arm 24 into engagement with the contact 23, the electric motor I9 is energized to operate the fan I6 to force conditioned air into the spaces to be cooled or conditioned The switch arm 24 may be operated in any suitable manner but for sim-.-. plicity it is shown as being manually operated.

The cooling coil 18 in the conditioning unit Il may be supplied with any type of refrigerant but for purposes of illustration, I have shown one end of the cooling coil l8 connected by a pipe 21 to a brine tank 28 and the other end or the cooling coil l8 also connected by a pipe 29 to the brine tank 28. Located in the brine tank 28 is a cooling coil (not shown) for cooling the brine.

. One end of this cooling coil in the brine tank 28 is connected by means of a pipe 38 to the suction side of a compressor 3|. A pipe 32 connects the outlet side of the compressor 3| to one end of a condenser coil 33. The other end of the condenser,coil 33 is connected by a pipe 34 to an expansion valve 35. The expansion valve 35 is in turn connected to the other end of the cooling coil in the brine tank 28 by means 01 a pipe 36, thus forming a refrigerating system of usual design for ,cooling the brine within the tank 28. The refrigerating system contains any usual type of refrigerating fluid. The compressor 3| may be driven through a'belt 31 by means of an electric motor 38. The electric motor 38 is connected by a wire 38 to the line wire 28 and by another wire 48 to an electrode of a mercury switch 4|. The mercury switch 4| may be operated by a thermostatic device 42 which is known in the through its two electrodes to energize the motor 38 to place the compressor 3| in operation to cause cooling of the brine within the tank 28. When the temperature of the brine 28 has de- 'creased to a predetermined value, the thermostatic device 42 tilts the mercury switch 4| in a counter-clockwise direction to break the elec-- tric circuit therethrough to stop operation of the electric motor 38 and the compressor 31 to prevent further cooling of the brine within the tank 28. In this manner, the brine within the tank 28 is maintained at a substantially constant temperature so that when the brine from the tank 28 is delivered to the cooling coil 8, a constant definite cooling effect will be imparted to the air passing through the conditioning unit l1.

Located on the outside of the building in any suitable manner so as to respond to outdoor atmospheric conditions, including temperature, solar radiation and wind in the same manner as the building is an outdoor controller 45. The outdoor controller 45 comprises a. metallic block 46 suitably mounted on a base 41. A cooling coil 48 is located in close proximity with the block 46 so that when cooling fluid flows through the cooling coil 48, the block 48 is cooled. The block 45 is heated by means of outdoor atmospheric conditions including the eflects of temperature, solar radiation and wind. Theblock 46 is hollowed out to receive a bimetallic element 48 suitably mounted on a post 58. The bimetallic ele ment 48 responds to the temperature of the block 48' and upon an increase in block temperature, the bimetallic element 48 moves in the direction of the arrow. The bimetallic element carries contacts 5| and 53 which are adapted to sequentially engage contacts 52 and 54, respectively, by reason of the fact that the distance between the contacts 5| and 52 is less than the distance between the contacts 53 and 54. The contacts 52 and 54 are adjustably mounted in an insulating block 55 to electrically insulate them from each other. To make sure that the outdoor atmospheric temperatures do not afiect the bimetallic element 48 directly, the open end of the block 46 is enclosed by a cover 56. All of the parts comprising the outdoor controller 45 are enclosed by means of a weather-tight casing 51 whereby the parts are not deteriorated by the elements.

Wires 58 and 68 connect a primary 6| of a step-down transformer 62, having a. secondary 63, across the line wires 28 and 2|, respectively. One end of the secondary- 63 is connected by a wire 64 to the adjustable contact 52 of outdoor controller 45. The other adjustable contact 54 is connected by wires 65 and 66 to one end of a relay coil 61. The other end of the relay coil 61 is connected by a wire 68 to the other end of the secondary 53. The bimetallic element 48 of the outdoor controller 45 is connected by means of a wire 68 to a contact 18. A switch arm 1| cooperating with the contact 10 is connected by a wire 12 to the junction of wires 65 and 66.

-Switch arms 13 and 14 cooperate with contacts 15 and 16. The switch arms 1|, 13 and 14 are operated by the relay coil 81 so that upon energizati'on of the relay coil 61, the switch arms 1|, 13 and 14 are moved to the left and upon deenergization of the relay coil 61, the switch arms 1|, 13 and 14 are moved to the right by means of springs or gravity or other means (not shown).

When the temperature of the metallic block 46 of the outdoor controller 45 decreases to a predetermined value, contact 5| moves into engagement with the contact 52. Upon a further slight decrease in block tem erature, contact 53 moves into engagement wi h the contact 54 to complete a circuit from the secondary 63, through wire 64, contacts 52, 5|, 53 and 54, wires 65 and 66, relay coil 61 and wire 68 back to the secondary 63. Completion of this circuit causes energization of relay coil 61 to move the switch arm 1|, 13 and 14 to the left. When the switch arm 1| moves into engagement with the contact 18, a holding circuit is completed from the secbndary 63,'through wire 64, contacts 52 and 5|,. bimetallic element 48, wire 68, contact 10, switch arm 1|, wires 12 and 66, relay coil 61 and wire 88 back to the secondary 83. This holding circuit maintains the relay coil 61 energized until the block temperature 46 has'risen sufficiently high to break contact between the contacts 5| and 52 at which time the relay coil 61 is deenergized and the switch arms 1|, 13 and 14 move to the right to cause switch arms 13 and 14 to engage contacts 15 and 16, respectively.

The outdoor controller 45 may be cooled by passing any type of cooling fluid through its coil 48. Cooled air which has been passed over the cooling coil |8 or the refrigerant leaving the expansion valve 35 could be used, but for purposes of illustration I have disclosed the use of brine from the tank 28. In this connection, a pipe 11 is connected into the pipe 21 extending between the brine .tank 28 and the cooling coil I8. This pipe 11 leads to one end of the cooling coil 48, located in the outdoor controller 45. v The other end of the cooling coil 48 is connected by a pipe 18 into the pipe 28 which also connects the cooling coil l8 to the brine tank 28. By reason of these connections, the cooling coils l8 and 48 are, in effect, connected in parallel. Located in the pipe 21 between the brine tank 28 and the pipe 11 is an electrically operated circulating pump 18. This pump 18 is connected by means of a wire 88 to the switch arm 14 and by means of a wire 8| to the line wire 2|. The contact 16, cooperating with the switch arm 14, is connected by a wire 82 to the line wire 28.v v When the relay coil 81 is deenergized upon an increase in block temperature above a given value, the switch arm 14 is moved into engagement with the contact aaeaito iii to complete an electric circuit for placing the electrically operated circulating pump I8 in operation to circulate brine through both of the cooling coils I8 and 48. In this manner, the temperature of the air delivered to the spaces in the building and the temperature of the block 48 are decreased. When the temperature of the block it decreases below a predetermined value, the relay coil 81 is energized in the. manner pointed out heretofore to move the switch arm 14 out of engagement with the contact 16 to break the electric circuit of the circulating pump 18 to stop further circulation/of the cooling brine through the cooling coils l8 and. In this manner, the circulating pump 19 is placed in and out of operation according to the temperature of the outdoor controller 45 to maintain predetermined temperatures within the building and within the outdoor controller 45.

If it is desired to do away with the circulating pump l8, gravitational flow of cooling fluid to 8i, acrdss the line wires 28 and 2|, respectively.

One end of the secondary BI is connected by a wire 82 to the contact 15. The switch arm 13, cooperating with the contact 15, is connected by wires 93 and 94 to the solenoid 84 of the valve A wire 95 connects the solenoid 88 of the I "valve 85 to the junction of wires 93 and 94. The

olenoid 84 of the valve 83 is connected by wires hand 98 to the other end of secondary 9|. The solenoid 86 of the valve 85 is connected by a wire 81th the junction of wires 98 and 98'. By reason of these connections, the solenoids 84 and 88, and consequently the valves 83 and 85, are connected in parallel for simultaneous operation. When the temperature of outdoor controller 45 has increased ab'ove a predetermined value, the relay coil 81 is deenergized to make contact between the switch arm 83 and the contact 15 to cause simultaneous energization of the solenoids 84 and 88, and therefore simultaneous opening of the valves 83 and 85. Cooling fluid is then permitted to flow from the brine tank 28 to both cooling coils i8 and 48. When the temperature of outdoor controller 45 has decreased below a predetermined value so as to energize the relay coil 61,

contact between the switch arm I3 and the contact i is broken todeenergize the solenoids 84 and 88 to close the valves 83 and 85 .to prevent the further supply of cooling fluid togthe cooling coils l8 and 48. Either the valves 83 or 85, or the circulating pump 18 may be used for controlling the supply or cooling fluidto the coils l8 and 40 iii) or the valves 88 and 85 and the circulating pump it may .both be used for controlling the supply of cooling fluid to the cooling coils l8 and 48, which exemplification is shown in Fig. 1.

Located in the pipe I1, extending between the pipe 28 and the cooling coil 48 of the outdoor controller 45, is a throttling or flow-regulating ture is substantially 122, a cooling system for the building must be selected which will maintain this 50 differential in temperature. The amount of cooling fluid delivered to the outdoor controller 45 is adjusted by the valve 99 to maintain the temperature within the outdoor controller at substantially 72 when the outdoor temperature is 122.- In other words, the amount of cooling eflect given to the building and the amount of cooling effect given to the outdoor controller 45 is made proportional to the heat gain to the building and the heat gain to the outdoor controller 45 caused by the higher outdoor temperature conditions. The amount of cooling fluid delivered to the outdoor controller 45 is controlled l by the throttling valve 89 and by properly adjusting the throttling valve 98, suficient cooling fluid may be delivered to the outdoor controller when the outdoor temperature is 122 to'maintain the outdoor controller temperature at a value slightly above 72 which maintains the contacts 53 and 54 open whereby cooling fluid is continuously supplied to the building and to the outdoorcontroller. In this manner, the building is maintained at a temperature of substantially 72 at an outdoor temperature of substantially 122. When the outdoor temperature falls below 122", the amount of cooling fluid supplied to the outdoor controller 45 is in excess of the amount needed to maintain its temperature slightly above 72 and the block 48 will be cooled below 72 to make contact between the contacts 5|, 52, 53 and 54 to energize the relay 6! \to shut off the further supply of cooling fluid to the building and to the outdoor controller. After the supply of cooling fluid has been so shut oil, the temperature of the controller 45 will rise to a point above 72 which will break contact between the contacts 5!, 52, 53 and 54 to deenergize the relay coil 81 to again .supply cooling fluid to the building and to the outdoor controller. In this manner, the outdoor controller cycles back and forth to control the cooling system to maintain a substantially constant temperature of 72 within the, building in accordance with the outdoor atmospheric conditions. From this it follows that the warmer it is outdoors, the longer the relay coil 81 will remain deenergized and the longer cooling fluid will be supplied to the building and the outdoor controller. It follows, also, that as the outdoor temperature decreases, the periods of operation of the cooling system for the building will likewise decrease until an outdoor temperature of 72 is obtained at which temperature the cycles of operation of the cooling system will be entirely prevented. C

Due to the fact that the heat gains to the building and to the outdoor controller are proportional to the amount of cooling given to the building and to the outdoor controller and due to the fact that the outdoor controller 45'resp0nds in a like manner to the same atmospheric conditions as the building, incldding temperature, solar radiation and wind, the building is maintained at a constant temperature of 72 whether there be a bright sun and no wind or a strong wind and no sun. v

If it be desired to have the building temperature increase as the outdoor temperature increases which appears to be the modern trend in building cooling systems, so that the building temperature rises above 72", an amount 01' 1 for each 3 rise in outdoor temperature, the size of the capacity of the cooling system may be decreased by 33%. In this manner, when the .outdoor temperatures, the cooling effect of the building coolingapparatus is decreased by onethlrd and therefore for every 3 rise in outdoor temperature above 72, the building temperature is allowed to rise 1 above 72.

Another way toaccomplish these results with my system but, using a full capacity cooling apparatus so that the temperature of the building 'is permitted to rise 1 with every 3 rise in outdoor temperature is to adjust the throttling valve 99 to supply a different amount of cooling fluid to the outdoor controller. By increasing the flow of cooling fluid to the outdoor controller to supply more cooling fluid to the same, the contacts til, 52, 53 and 54 will not remain out of contact when the temperature of the outdoor atmosphere rises to 122. By increasing the amount of flow of cooling fluid to the outdoor controller in an excess of 50%, the outdoor controller will operate only two-thirds of the time when the outdoor temperature is 122. With a full capacity cooling system for the building which is capable to maintain the temperature of the building at 72 under 100% operation when the outdo r temperature is 122, two-thirds of. the operation of such a cooling system will permit the building temperature to rise one-third of the diiferential of 50 to a point corresponding to substantially.89.

perature will rise 1 withev'ery 3 rise in outdoor temperature.

It is well-known that when a large number of people congregate. in a building such-as a theatre, the temperature of the building is increased by body heat. The congregation of a large number of people therefore increases the cooling load of the building. It is therefore necessary to increase the amount of cooling eflect delivered to the building with'res'pect to the amount of cooling delivered to the building when no people or a relatively small number of people are present within the building. Y By decreasing the amount of cooling fluid delivered to the outdoor controlier 45 which causes an increase in the time of operation of the building cooling system forms an easy means for compensating for cooling load changes caused by the congregation of a large number of people within the building. This change of flow of cooling fluid to the outdoor controller and consequently the change of the cooling system for compensating for the extra cooling load is easily obtained by adjusting the throttle valve 99.

From the above, it is seen that by adjusting the valve 99 the cooling efiect of the cooling system of the building may be adjustedso that a constant temperature within the building may be maintained regardless of outdoor atmospheric conditions or a temperature within the building be obtained or the cooling system may be cor- A modified cooling system is shown in Fig. 2 to be applied to a building having a side wall I0 and a pluralityof spaces to be cooled II. Cooled or conditioned air is delivered to the spaces II in this modification as in the previous modification through grills I2 and ducts I3, I4 and I5 by means of a fan I6. The fan I6 draws air through a conditioning unit I1, equipped with a coil I8 as in the previous modification. The fan is driven by an electric motor I9 which receives its power from line wires 20 and 2I and the fan motor I9 is stopped and started by means of the manually operated switch 24 as, in the previous modification.

In this modification, cooling fluid is supplied to the cooling coil I8 through a pipe IOI which receives its supply of cooling fluid from a source of cooling fluid (not shown) through a pipe I03. The source of cooling fluid may be the usual city water system, an artesian well or any other means. The cooling fluid after it has passed through the cooling coil I8 is lead away to a place of disposal by means of a pipe I04. The supply of cooling fluid to the coil I8 is controlled by avalve I02 so that when the valve I02 is opened, cooling fluid is allowed to flow through the cooling coil I8 to cool the air passed to the spaces to be cooled II. The valve I02 is operated by a valve stem I05 to which is connected one end of a pitman I01 by means of a pin I06. The other end of the pitman I01 is connected to a crank pin I08 mounted on a gear I09. The

gear I09 is mounted on a shaft IIO for rotation therewith and the gear I09 is driven through a reduction gear train III by a rotor II2 upon energization of a field H3. The shaft IIO which carries the gear I09 also carries cams H4 and H5 for rotation therewith. The cams H4 and H5 operate contact arms H6 and H1, respectively. When the high dwells of the cam II4 engage the contact arm I I6, the contact arm H6 is moved into engagement with a contact II8. When the high dwell of the cam II5 engages the contact arm II1, the contact arm H1 is moved into engagement with a contact H9 and when the low dwell becomes operative, the contact arm II1 moves into engagement with a contact I20.

Located outside of the building in any suitable manner so as to respond to atmospheric conditions, including temperature, solar radiation and wind velocity in the same manner as the building, is an outdoor controller I2I which is identical to that disclosed in the previous modification with the exception that a heater resistance I22 is used in placeof the cooling coil 48 of the previous modification. The heater I22 raises the temperature of the block 46 above the surrounding ambient outdoor temperature and the block 46 is cooled by this surrounding outdoor ambient temperature as varied by solar radiation and wind.

The same transformer 62 and the same relay coil 61 are utilized in operating switch arms 1|, I23 and I24 as in the previous modification. The wiring connections between the outdoor controller I2I and the relay coil 61 are identical with those disclosed above. The relay coil 61 controls the operation of switch arms II, I23 and I24 and upon energization of relay coil 61, the switch arms 1I, I23 andl24 are moved to the left into engagement with contacts 10, I25 and I21, respectively. Upon deenergization of the relay coil 61, the switch arms 1|, I23 and I24 are moved to the right out of engagement with their respective contacts and the switch arm I23 is moved into 76 engagementwith a contact I23. From this, it is seen that when the temperature of the block 46 of the outdoor controller I2I is above a predetermined value, the relay coil 61 is deenergized and the switch arms 1|, I23 and I24 are moved to the right and that when the temperature of the block 46 is below a predetermined value, the relay coil 51 is energized and the switch arms II, I23 and I 24 are moved to the left.

The contact I25 is connected by a wire I28 to the contact II9 of the valve motor and the contact I26 is connected by a wire I29 to the contact Itt. Wires I30 and I3I connect a primary I32 of a step-down transformer I33, having a secondary I34, across-the line wires 20 and 2I One end of the secondary I34 is connected by awire I35 to one end of field II 3. II t is connected by wires I 36 and I3'I to the contact arm III. The contact arm H6 is connected by a wire I38 to the junction of wires I36 and It'I. The contact I it of the valve motor is connected by means of wires I39 and I42 to the switch arm I23. The other end of secondary I3I is connected bya wire I4I to the junction of wires I33 and I40.

, When the temperature ofthe block 46 falls below the predetermined value, the relay coil Si is energized to move the switch arm I 23 tothe left into engagement with the contact I25 to complete a circuit from the secondary I34, through wires I4I, I40, switch arm I23, contact I25, wire I22, contact II9, contact arm I", wires I31 and I36, field II3 and wire I35 back to the secondary I34. Completion of this circuit causes energization of the field II3 to rotate the rotor H2 and cause closing movement of the valve I02. When the valve I 02 has started to close, the cam II4 moves the contact arm I I6 into engagement with the contact II8 to complete a maintaining circuit from the secondary I34, through wires MI and I39, contact H8, contact arm H6, wires I35 and I36, field II3 and wire I35 back to the secondary I34. This maintaining circuit insures complete closing movement of the valve I02. When the valve I02 is completely closed, contact between the contact arm I I6 and the contact I I8 is broken to prevent further operation of the valve and the contact arm II! is moved into engagement with" the contact I20 to position the valve motor for valve opening operation. When the temperature of the block 46 of outdoor controller I2I rises above the predetermined value, the relay coil 8I is deenergized to move the switch arm I23 into engagement with the contact I 26 to complete a circuit from the secondary I34 through wires I M and I4l'l, switch arm I23, contact I25, wire I29, contact I20, contact arm II I, wires I31 and I36, field II3 and wire I35 back to the secondary I34. Completion of this circuit causes energization of the field II3 to move the valve I02 to an open position. Complete opening movement of the valve I02 is insured by movement of contact arm IIt into engagement with the contact II ll which completes the above referred to maintaining circuit. From the above, it is seen that when the temperature of the block 46 is above a prede termined value, the valve I02 is moved to an open position to supply cooling fluid to the cooling coil I3 and when the temperature of block 46 is below the predetermined value, the valve I02 is moved to 'a closedposition.

The contact IN is connected by a wire I42 to the line wire 20. The switch arm I24 which cooperates with the contact I2'I is connected by a wire I43 to a variable resistance I44 which is in The other end of field turn connected to an ammeter I45. The ammeter I45 is connected bya wire I46 to one end of the heater I22 of outdoor controller I2I. Ihe other end of the heater I22 is connected by a wire I" to the other line wire 2I. When the temperature of block 45 falls below the predetermined value, the relay coil 61 is energized to move the switch arm I24 into engagement with the contact Hi to energize the heater I22 to cause heating of the block 46. When the temperature of block 46 rises above the predetermined value, relay coil M is deenergized to break contact between-the switch arm I24 and the contact I21 to prevent the further supplypf heat to the outdoor controller I2I. In this manner, the outdoor controller I2I is maintained at a substantially constant temperature. The variable resistance I44 and the ammeter I45 provide a means for adjusting and visually indicating the amount of heat supplied to the outdoor controller I2I.

In describing the operation of this modification, it is assumed that the maximum outdoor 3 temperature that may exist is 122 and that the cooling system for the building is oi such capacity as will maintain the temperature of the building at 72 when the outdoor temperature is 122 or, in other words, maintain a difl'erential in temperature between the building and the outdoor ambient temperature of 50". When the outdoor temperature is 72, the variable resistance I44 is so adjusted as to deliver so much heat to the outdoor controller I2I that the temperature of block 46 will remain at substantially 122. The contacts 5|, 52, 53 and 54 are so adjusted that they will just be maintained in engagement when the block temperature is 122 and, therefore, the relay coil 61 will remain energized at an outdoor ambient temperature of. 72. Under such conditions, the switch arm I23 will remain in engagement with the contact I to maintain. the valve I 02 closed allowing no cooling fluid to be supplied to the coil I3. By reason of this adjustment, when the outdoor temperature is 12", the building is not cooled and the building temperature remains at the ambient temperature of 72. When the outdoor temperature rises-above 72, the block temperature tends to rise the same amount and since the amount of heat delivered to the block 46 is constant, the temperature 01' the block 46 rises above 122 which causes deenergizatlon of the relay coil ti and consequent opening of the valve I02to supply cooling fluid to the r-ooling coil I3. The building is thereby cooled by temperatures, the relay coil 51 is deenergized and the valve I 02 is opened a relatively short time and periods of valve opening vary from zer'b at 72 to 100% at 122 of outdoor ambient temperature to maintain'a constant temperature-within the building of 72 at all times.

Since the outdoor controller I2I responds similarly to the same atmospheric conditions as the building, including outdoor temperature and solar radiation and since the building temperature is controlled by the oudoor controller, a substantially constant average temperature may be maintained within the building regardless of the effects of a sun-shiny or dark day.

In order to control the temperature of the building in this modification so that the temperature of the building may rise as the outdoor temperature rises in a ratio of 1 to 3, the capacity of the building cooling system may be decreased by one-third as in the previous modification. Another way of controlling the temperature within the building so that the building temperature may rise 1 above 72 with every 3 rise in temperature of outdoor temperature above 72, the amount of heat delivered to the outdoor controller and the contact setting of the outdoor controller may be increased by 50%. To get theseresults, the contact setting of the outdoor controller is raised 50% of the difi'erence between the present setting and the base temperature or 25. The contact setting is, therefore, changed from 122 to 147. The variable resistance I44 is varied to increase the amount of heat to the outdoor controller I2I by 50% so that sufiicient heat is supplied to maintain the contacts 5|, 52, 53 and 54 just made to maintain the relay coil 61 energized when the outdoor ambient temperature is 72. By reason of this new setting, when the outdoor temperature is 122, the contacts of the controller I2I make contact one-third of the time and thereby the valve I02 is closed one-third of the time. Therefore, the valve isopened only two-thirds of the time and the building cooling system has only two-thirds of its maximum cooling eflect available when the outdoor temperature is 122. From this, the temperature of the building is allowed to rise from 72 to 89 which is one-third of the differential between the base temperature of 72 and the existing outdoor ambient temperature of 122. Likewise, when the outdoor temperature decreases below 122, the oil periods of the cooling system are increased by one-third so that the building will not be maintained at 72 but at a temperature above 72 which is one-third the difference between the ambient temperature and the base temperature. Therefore, by changing the contact setting of.and the heat in-put to the outdoor controller in the manner above described, the building temperature is allowed to rise 1 above 72 for every 3 rise in outdoor temperature above 72.

In the-cooling system disclosed by this modification, provision is made also for controlling the cooling equipment of a building in accordance with outdoor atmospheric conditions including temperature and solar radiation so that the building may be maintained at a given constant temperature regardless of outdoor atmospheric conditions or may be maintained at a temperature which increases as the outdoor temperature increases. By decreasing the control setting of and the heat in-put to the outdoor controller, the cooling system of this modification may be adjusted to compensate for increased cooling loads caused by the congregation of a large number of people in the building.

Referring now to Fig. 3, I have disclosed the preferred form of my invention and for purposes of illustration, I have shown my control system applied to a building, having an outside wall I and a plurality of spaces to be conditioned II.

Conditioned air is delivered to the spaces II by means of grills I2 and'air ducts I3, I4 and I6. Air is supplied to these ducts by means of a fan I6 which draws air through a conditioner I1. The fan I6 is operated by an electric motor I9 in exactly the same manner as in the previous two modifications, the motor I9 receiving its supply of power from the line wires 20 and 2I under the control of the switch arm 24. Located in the conditioning unit I1 is a cooling coil I8. Also located in the conditioning unit I1 is an air cleaner I50 which may take'the form of any known air cleaner. Air is delivered into the conditioning unit I1 through ducts I6I and I52, the duct I5I being used for return air and the duct I52 being used for fresh air. The relative proportion of air delivered by ducts I5I and I52 is controlled by suitably operated. dampers I53 and I 54 as is known in the art.

Located on the conditioning unit I1 is an electric motor I55 which drives a compressor I51 by means of a belt I56. The outlet side of the compressor I51 is connected by a pipe I58 to one end of a condenser I59. The other end of the condenser I 59 is connected to an expansion valve I60 and the expansion valve I60 is in turn connected by a pipe I6I to the other end of cooling coil I8. The other end of cooling coil I8 is connected by a pipe I62 to the suction side of the compressor I51 thereby forming a complete refrigerating unit of the usual design. This refrigerating unit is filled with any suitable type of refrigerant, When the compressor I51 is placed in operation upon energization of motor I55, the cooling coil I8 is cooled and the air delivered to the spaces II of the building is likewise cooled.

Located outside of the building so as to respond to atmospheric conditions, including temperature, wind and solar radiation is a modified form of an outdoor, controller I65. This outdoor controller I65 comprises a block I66 mounted on a suitable base I61. Located in close proximity to the block I66 is a heater I68. The block temperature is raised by the action of heater I66 and cooled by the action of the outdoor atmosphere including the effects of temperature, solar radiation and wind. The block I66 is hollowed out to receive a bimetallic element I69. The bimetallic element I69 is mounted on a bracket I10, pivotally carried by a support I12. The bimetallic element I69 carries contacts I13 and I14 which are adapted to sequentially engage contacts I15 and I16. The contacts I15 and I16 are insulated from each other and adjustably mounted in an insulating block I11 secured in the block I66. A cover I18 encloses the open end of block I 66 so that the bimetallic element I 69 will respond directly to the temperature of block I66 and not be affected directly by outdoor atmospheric conditions. The bracket I is provided with an upwardly extending adjusting arm I19. A casing I80 encloses the elements of outdoor controller I65 to prevent their deterioration by the elements. The base I61 is provided with an upturned extension i8I upon which is mounted a second bimetallic element I69 by means of a nut and screw arrangement I 82. The adjusting arm I19 and the bimetallic element I83 are connected together by a suitable linkage arrangement I 69 which extends through openings I85 and I 86 in the casing I80 and the block I66, respectively. The bimetallic element I69 responds to the blockitemperature and the bimetallicelement I83 responds to the outdoor ambient temperature directly. Upon an increase inoutdoor ambient temperature, the bimetallic element I83 moves to the left in the direction shown by the arrow and upon an increase in the block temperature, the bimetallic element 169 moves to the right in the direction shown by the arrow. The bimetallic element I83 is more effective than the bimetallic element I69 and for purposes of illustration, it is assumed to be twice as efiective.

For purposes of illustration, assume that the bimetallic elements I69 and I83 and the contacts 119 and I18 are so arranged and adjusted that with a block temperature of 72 and'an outdoor ambient temperature of 72, the contacts I13, I19, I15 and I16 are just on the point of breaking. Assume that the outdoor ambient temperature rises 5 from 72 to 77,this forces the bimetallic element I69 to theleft and since the bimetallic element I83 is twice as effective as the bimetallic element I69, the block temperature must rise 19 above 72 or to 82 before contact between contacts I18, I15, I14 and I18 is broken. Likewise, for a 10 rise in outdoor ambient temperature affecting'the bimetallic element I88, a block temperature 20 above 72 or 92 is required to break the contacts. From this it is seen that the diiference between the block temperature and the ambient temperature is equal to the difference between the ambient temperature and the base temperature, the base temperature being 72 in this illustration. Stating it another way, the block temperature rises twice as fast above 72 as the ambient temperature does so that with a maximum outdoor temperature of 122, the block temperature must be 172 to break contact between the contacts of the outdoor controller I65. By this construction, the block temperature required to break contact between the contacts is adjusted upwardly by 'an increase in outside ambient temperature.

A relay coil designated at I81 controls the operation of switch arms I88 and I89 so that upon energization of the relay coil I81, the switch arms I88 and I89 are moved into engagement with contacts I99 and HI and upon deenergization of relay coil I81, the switch arms I98 and I89 are moved out of engagement with their respective, contacts by means of springs or gravity or other means (not shown). Wires I92 and I98 connect a primary I94 of a stepdown transformer I95, having a secondary I98,

across the line wires 29 and 2I, respectively.

One end of secondary I96 is connected by a wire I91 to the contact I19 of outdoor controller 169. The contact I16 is connected by wires I98 and 199 to one end of the relay coil I81. The other end of the relay coil I81 is connected by a wire 899 to the other end of secondary I96. The bimetallic element I69 is connected by a wire 891 to the contact I99 and the switch arm I88 cooperating with the contact I98 is connected by a wire 892 to the junction of wires I98 and When the temperature of the block I69 falls below a predetermined value, as determined by the combined action of the bimetallic elements I99 and I89, contacts I13 and I16 and contacts I19 and I16 make contact to complete a circuit from the secondary I98 through wire I91, contacts I16, I19, I19 and I16, wires I99 and I99, relay coil I81 and wire 299 back to the secondary I98. Completion of this circuit causes energization of relay coil I81 and movement of the switch arms I88 and I89 into engagement with the contacts I99 and I9I. When the switch arm I88 engages the contact I99, a maintaining circuit is completed from the secondary I98, through wire I91, contacts I15 and I13, bimetallic element I69, wire 29I, contact I99, switch arm I88, wires292 and I99, relay coil I81, and wire 299 back to the secondary I96 to maintain tween the contacts I13 and I15 is broken by an increase in block temperature as determined by the combined action of the bimetallic elements I69 and I 88.

.the relay coil I81 energized until contact be- The contact I9I is connected by a wire 293 to the line wire 29, the switch arm I89 cooperating with the contact I9I is connected by a wire 299 to the electric motor I55. I he electric motor I55 is in turn connected by a wire 295 to the line wire 21. The switch arm I89 is also connected by a wire 298 to a variable resistance 291 which in turn is connected to an ammeter 298. The ammeter, 298 is connected by wire 299 to one end of the heater I88, the other end of heater I68 being connected by a wire 219 to the line wire 21.

When the temperature, of the outdoor controller I68 drops below a predetermined value to energize the relay I81 to move the switch arms I88 and I89 into engagement with the contacts I99 and I9I, a circuit. is completed from the line wire 29, through wire 283, contact I9I, switch arm I89, wire 294, motor I55 and wire 295 back to the line wire 2| and a circuit is completed from the line wire 29 through wire 293, contact I9I, switch arm I89, wire 296, variable resistance 291, ammeter 298, wire 299, heater I68 and wire 2I9 back to the line wire 2| to cause operation of the motor I 55 and energization of heater I68. Operation of the motor I55 causes cooling of the cooling coil I8 and consequent cooling of the building and energization of heater I68 causes heating of the block I66 of outdoor controller I65. The variable resistance 291 and the ammeter 298 provide a means for adjusting and visually indicating the amount of heat delivered to the block I66.

Assume in this modification asin the previous modifications that the maximum outdoor temperature that may occur is 122 and that the building cooling apparatus and energizatlon of the heater I68.

As pointed out above, with each degree rise in outdoor ambient temperature above the base temperature of 72, the contact setting of the outdoor controller I66 is raised two degrees above the base setting of 72, by the action of the bimetallic element I88. Therefore, with an outdoor temperature of 77, the contacts of the outdoor con troller are automatically set for 82 and with an outdoor temperature of 82, the contacts are ad justed to 92". Likewise, when the outdoor temperature is at its maximum of 122, the controller contacts are adjusted to-a 172 temperature setting. Since it is necessary to operate the building cooling apparatus 100% of the time when the outdoor temperature is 122 to maintain 'a building temperature of 72, the contacts I13, I14, I15 and I16 must be maintained in engagement at this maximum outdoor temperature of 122. Therefore, the variable resistance 201is adjusted to supply sufiicient heat to the outdoor controller I65 to just maintain the temperature of the block I66 at 172 to just maintain the contacts I13, I14, I15 and I16 in engagement, In other words, sufficient heat is supplied to the block I66 to maintain the temperature thereof just 50.

above the outside ambient temperature by reason of the substantially straight line relation of the heat loss characteristics of the outdoor controller I65, the same amount of heat applied to the outdoor controller 100% of the time will maintain the 50 differential in temperature between the block temperature and the outdoor ambient temperature even though the outdoor ambient temperature be 122 or 72.

If the outdoor temperature should drop 10 from 122 to 112, the differential between the base temperature of 72 and the ambient temperature would be only 40 instead of 50 as before. Therefore, the building cooling apparatus would only have to operate of the time to maintain the building temperature at 72. A drop of 10 in ambient temperature lowers the temperature setting of the outdoor controller 20 from 172 to 152. Since the amount of heat delivered to the block I66 is constant and is sufiicient to maintain a 50 differential in temperature between the block temperature and the out.- door ambient temperature, operation of the heater would cause a. block temperature of 112 plus 50 or 162. However, the contact settings have been automatically adjusted by the bimetallic element I86 to break contact at substantially 152 to maintain only a 40 diiferential between the block and the outdoor ambient temperature. It therefore follows that the heater I68 is capable of supplying too much heat to the outdoor controller and need be only energized 80% of the time to maintain this 40 differential between the block temperature and the outdoor ambient temperature. The bimetallic element I69 responding to the block temperature and controlling the contacts I73, I14, I15 and I16 causes energization of the relay coil I81 and consequently the heater I68 only 80% of the time. Since the building cooling apparatus is operated concurrently with the energization of the heater I68, the building apparatus is operated only 80% of the time and therefore the building temperature is maintained at 72.

In a like manner, if the ambient temperature should drop to 97, giving a differential of 25 between the base temperature of 72 and the ambient temperature of 97, the contact setting of the outdoor controller is automatically adjusted to 122, giving a differential of 25 between the outdoor ambient temperature of 97 and the contact setting. Since the heater I68 is capable of maintaining a 50 differential in temperature by 100% operation, it need operate only 50% of the time to maintain the 25 differential. Consequently, the buildingv cooling means is operated only 50% of the time and the building is maintained at a substantially constant temperature of 72. Therefore, the building cooling apparatus is operated from 100% of the time at an ambient temperature of 122 to zero percent at I an ambient temperature of 72 to maintain a substantially constant temperature of 72 within the building regardless of outdoor ambient temperatures.

In order to control the temperature of the building in thissmodification so that the temperature of the building may rise" as the outdoor temperature rises in a ratio of 1 to 3, the capacity of the building cooling system may be decreased by one-third as in the previous modifications. Such a mode of operation may also be accomplished in this modification by merely adjusting the variable resistance 20.! to vary the supply of heat to the outdoor controller I65. Specifically, the amount of heat delivered to the outdoor controller may be increased by 50% to allow the building temperature to rise 1 above 72 for every 3 rise in ambient temperature above 72. An increase of 50% in the supply of heat makes it possible to maintain a differential of 75 between the ambient temperature and the block temperature. Therefore, with an ambient temperature of 122, the block temperature could assume a temperature value of 122 plus 75 or 197 but the contact settings are set for 172 by the bimetallic element I83 and consequently the heater I68 need be energized only two-thirds of the time to maintain a block temperature of 172. Energization of the heater I68 two-thirds of the time means operation of the building cooling apparatus only two-thirds of the time at 122 ambient temperature. Thus, the cooling apparatus has only two-thirds of its cooling effect and cannot maintain the 50 differential between the ambient temperature of 122 and the base temperature of 72 but only two-thirds of it. The building is therefore maintained at 122 minus two-thirds of 50 or 89 when the outdoor temperature is 122. In a like manner, the period of operation of the cooling apparatus as determined by the outdoor ambient temperatures are all decreased by one-third so that for each 3 rise in ambient temperature above 72, the building temperature is allowed to rise 1 above 72.

Here as in the previous modifications, the outdoor controller I65 responds in a similar manner to the same atmospheric conditions as the building including temperature, wind and solar radiation and predetermined temperatures may therefore be maintained in the building regardless of the effects of a dark, windy day or a still, sunshiny day.

In this modification, provision is also made for adjusting the control system to compensate for changes in the cooling load in the building caused by the congregation of a large number of persons in the building. As pointed out above, the body heat of a large number of persons within the building tends to materially increase the temperature in the same and thereby increases the cooling load on the building cooling apparatus. This compensated efiect may be accomplished in this modification by merely adjusting the variable resistance 201. The variable resistance is properly adjusted to decrease the amount of heat delivered to the outdoor con troller I65 by the heater I68 which increases the periods of operation of the building cooling Although I have disclosed for purposes of illustration definite temperature values, heat values and contact settings, I do notintend to be so limited since various values may be assumed to meet various operating conditions. In disclosing my invention, I have shown and described three specific modifications for purposes of illustration but my invention is to be limited only by the scope of the appended claims and the prior art. llll I claim as my invention:

1. In a system of the class described, temperature changing means for an enclosure, a controller including temperature changing means and thermostatic means, the thermostatic means in controlling both temperature changing means, and other thermostatic means for adjusting the first thermostatic means.

2. In a system of the class described, temperature changing means for an enclosure, an out- W door controller affected by the same atmospheric conditions as the enclosure, thermostatic means and temperature changing means in said outdoor controller, the thermostatic means controlling both temperature changing means, and means 2d responsive to outdoor. temperatures for adjusting the thermostatic means.

3. A structure exposed to outdoor atmospheric conditions, temperature changing means for the I structure, an enclosure exposed to the same out- 80 door atmospheric conditions, temperature chang-' ing means for theenclosure, and means responsive to the temperature of the enclosure and outdoor temperatures for controlling both temperature changing means to maintain temperatures in the enclosure that vary with changes in outdoor temperature and to maintain a substantially constant temperature in thestructure.

4. A structure exposed to outdoor atmospheric conditions, temperature changing means for the 40 structure, an enclosure exposed to the same outdoor atmospheric conditions, temperature changing means for the enclosure, and means responsive to the temperature of the enclosure and outdoor temperatures for controlling both tem perature changing means to maintain temperatures in the enclosure that vary with changes in outdoor temperature and to maintain temperatures in the structure that increase as the outdoor temperature increases.

5o 5. In a temperature control system for an enclosure, comprising, in combination, cooling means for the enclosure, 2. controllerlocated outside of the enclosure .and affected by the same atmospheric conditions as the enclosure, said as controller including thermostatic means responsive to the temperature thereof and heating means= of suflicient capacity to maintain the temperature of the controller at a desired value, and means controlled by the thermostatic means w for alternately operating the enclosure cooling means and the controller heating means to maintain desired temperatures in the enclosure.

6. In a temperature control system for an enclosure, comprising, in combination, cooling means for the enclosure, a controller located outside of the enclosure and affected by the same atmospheric conditions as the enclosure, said controller including thermostatic means responsive to the temperature thereof and heating means having sufficient capacity to maintain the temperature of the controller at a desired value,

thermostatic means responsive to, outdoor temperature for adjusting the controller thermostatic means to raise the setting thereof as the outdoor temperature increases, and means contemperatures in the controller, and means for trolled by the controller thermostatic means for controlling the enclosure cooling means and the controller heating means to maintain desired temperatures in the enclosure.

7. In a system of the class described, tem- 5 perature changing means for an enclosure, an outdoor controller including temperature changing means and thermostatic means, saidthermostatic means controlling said controller temperature changing means in a manner to maintain 10 said controller between predetermined temperature values, and means for energizing said enclosure temperature changing means when said controller temperature changing means is deenergized. l5

8. In a system of the class described, temperature changing means for an enclosure, an outdoor controller including temperature changing means and thermostatic means, said thermostatic means controlling said controller tempera- 20 ture changing means in a manner to maintain said controller between predetermined temperature values, means for energizing said enclosure temperature changing means when said controller temperature changing means is deener- 25 gized, and means for adjusting one of the temperature changing means.

9. In a temperature control system for a building, the combination of, cooling means for the building, a controller located outside of the building and affected by the same atmospheric conditions as the building, said controller including thermostatic means responsive to the temperature thereof and temperature changing means of sufiicient capacity to maintain the temperature of the controller at a desired value, means controlled by the thermostatic means for controlling the building cooling means and the controller temperature changing means to maintain desired temperatures in the controller, the m cooling efiect of the building cooling means and the temperature changing efiect of the controller temperature changing means being so proportioned with respect to the effect of outside atmospheric conditions on the building and the 5 outdoor controller that the cooling efiect of the building cooling means upon the building is less than the temperature changing effect of the controller temperature changing means upon thereof and temperature changing means of sufficient capacity to maintain the temperature of the controller at a desired value, means controlled by the thermostatic means for controlling the building cooling means and the controller temperature changing means to maintain desired relatively adjusting the cooling effect of the building'cooling'meansand the temperature changing efiect of the controller temperature changing means with respect to the effects of outside atmospheric conditions on the building and the out [0 door controller in a manner to cause the cooling effect of the building cooling means to be less upon the building than the temperature changing eifect of the controller temperature changing means is upon the outdoor controller whereby the sufficient capacity to maintain the temperature of the controller at a desired value, means controlled by the thermostatic means for controlling the building cooling means and the controller temperature changing means to maintain desired temperatures in the controller, and means for adjusting the temperature changing effect of the controller temperature changing means with respect to the cooling effect of the building cooling means and the effects of outside atmospheric conditions on the controller and building in a manner cause the temperature changing effect of the controller temperature changing means upon the outdoor controller to be greater than the cooling efiect of the buildingcooling means upon the building whereby the building temperature increases as the outside temperature increases, the amount of increase in building temperature per unit increase in outside temperature varying with the amount of adjustment.

12. In a temperature control system for a building, the combination of, cooling means for the building, a controller located outside of the building and afiected by the same atmospheric conditions as the building, said controller including thermostatic means responsive to the temperature thereof and cooling means of sufcient capacity to maintain the temperature of the controller at a desired value, means controlled by the thermostatic means for controlling the building cooling means and the controller cooling means to maintain desired temperatures in the controller, the cooling effect of the building cooling means and the cooling effect of the con troller cooling means being so proportioned with respect to the effect of outside atmospheric conditions on the buiding and the outdoor controller that the cooling effect of the building cooling means upon the building is less than the cooling efiect of the controller cooling means upon the outdoor controller whereby the building temperature increases as the outdoor temperature increases.

13. In a temperature control system for an enclosure comprising, in combination, cooling means for the enclosure, acontroller located outside of the enclosure and affected by the same atmospheric conditions as the enclosure, said controller including thermostatic means responsive to the temperature thereof and heating means of sufficient capacity to maintain the temperature of the controller at a desired value, means controlled by the thermostatic means for controlling the enclosure cooling means and the controller heating means to maintain desired temperatures in the controller, and means for relatively adjusting the cooling efiect of the enclosure cooling means upon the enclosure and the heating eifect of the controller heating means upon the outdoor controller with respect to the effects of outside atmospheric conditions on the enclosure and the outdoor controller in a manner to cause the enclosure temperature to remain substantially constant regardless of outside temperatures or to cause the enclosure temperature to increase as the outside temperature increases.

14. In a temperature control system for an enclosure, comprising, in combination, cooling means for the enclosure, a controller located outside of the enclosure and affected by the same atmospheric conditions as the enclosure, said controller including thermostatic means responsive to the temperature thereof, and heating means of sufficient capacity to maintain the temperature of the controller 'at a desired value, means controlled by the thermostatic means for controlling the enclosure cooling means and the controller heating means to maintain desired temperatures in the controller, and means for adjusting the temperature setting of the controller thermostatic-means and the heating effect of the controller heating means upon the outdoor controller with respect to the cooling effect of the enclosure cooling means upon the enclosure and the effects of outside atmospheric conditions on the outdoor controller and the enclosure in a manner to cause the enclosure temperature to remain substantially constant regardless of outside temperatures or to cause the enclosure temperature to increase as the outside temperature increases.

15. In a temperature control system for an enclosure, comprising, in combination, cooling means for the enclosure, a controller located outside of the enclosure and affected by the same atmospheric condition as the enclosure, said controller including thermostatic means responsive to the temperature thereof and heating means of sufiicient capacity to maintain the temperature of the controller at a desired value, means controlled by the thermostatic means for alternately operating the enclosure cooling means and the controller heating means to maintain desired temperatures in the controller, and means for relatively adjusting the cooling effect of the enclosure cooling means upon the enclosure and the heating efiect of the controller heating means upon the outdoor controller with respect to the effects of outside atmospheric conditions on the enclosure and the outdoor controller in a manner to cause the enclosure temperature to remain substantially constant regardless of outside temperatures or to cause the enclosure temperature to increase as the outside temperature increases.

16. In a temperature control system for an enclosure, comprising, in combination, cooling means for the enclosure, a controller located outside of the enclosure and afiected by the same atmospheric conditions as the enclosure, said controller including thermostatic means responsive to the temperature thereof and heating means having sufiicient capacity to maintain the temperature of the controller at a desired value, thermostatic means responsive to outdoor temperature for adjusting the controller thermostatic means to raise the setting thereof as the outdoor temperature increases, means controlled by the controller thermostatic means for controlling the enclosure cooling means and the controller heating means to maintain-desired temperatures in the controller, and means for relatively adjusting the cooling effect of the enclosure cooling means upon the enclosure and the heatingeffect of the controller heating means upon the outdoor controller with respect to the eifects of outside atmospheric conditions on the enclosure and the outdoor controller in a manner to cause the enclosure temperature to remain substantially constant regardless of outside temperatures or to cause the enclosure temperature to increase as the outside temperature increases.

17. In refrigerating apparatus, the combination of means defining a zone to be cooled, an evaporator for cooling the media in said zone, means for circulating refrigerant through said evaporator, and means for intermittently effecting operation of the circulating means for predetermined periods of time and irrespective of temperature conditions within said zone, said means including an element responsive primarily to the temperature of the air exterior of said zone for varying the duration of said periods of time that the circulating means is operated.

18. In refrigerating apparatus, the combination of means defining a zone to be cooled, an evaporator for cooling the media in said zone, means for circulating refrigerant through said evaporator, means for intermittently efiecting operation of the circulating means so that it is active and inactive for predetermined periods of time irrespective of temperature conditions within said zone and means responsive primarily to the temperature of the atmosphere exterior of said zone for varying the relation between the period of time that the circulating means is active and the period of time that it is inactive.

19. In refrigerating apparatus, the combinetion of means defining a zone to be cooled, an evaporator for cooling the media in said zone. means for circulating refrigerant through said evaporator, a motor for driving the circulating means, and means for intermittently effecting energization of the motor for predetermined periods of time and irrespective of temperature conditions within said zone, said means including an element responsive primarily to the temperature of the air exterior of said zone for varying the duration of said periods of time that the motor is energized.

20. In a refrigerating apparatus, the combination of means defining a zone to be cooled, a cooling coil for cooling the media in said zone, means for regulating the circulation of refrigerant through the cooling coil, a motor for driving the same, switch means for controlling energization of the motor, a thermal responsive device disposed in heat transfer relation with the ambient atmosphere exterior of said zone for actuating the switch means, a heater disposed in heat transfer relation with the device, and means for energizing the heater during periods when the motor stops circulation of refrigerant through the cooling coil and for deenergizing the heater during periods when the motor causes circulation of re frigerant through the cooling coil.

DANIEL G. 'rAYLoR.

CERTIFICATE OF CORRECTION" Patent N0. 2,222,159. November 19, 191m.

DANIEL G, TAYLOR.

v It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 6, first column, line 69, for the word "control" read contact-; page 10, first column, line ELL, claim 11, before '"cause" insert "to" and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent office.

Signed and sealed this 1st day of April, A. D. 19m.

Henry Van AIsdale (Seal) Acting Commissioner of Patents 

